KVM: VMX: enable guest access to LMCE related MSRs

On Intel platforms, this patch adds LMCE to KVM MCE supported
capabilities and handles guest access to LMCE related MSRs.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
[Haozhong: macro KVM_MCE_CAP_SUPPORTED => variable kvm_mce_cap_supported
           Only enable LMCE on Intel platform
           Check MSR_IA32_FEATURE_CONTROL when handling guest
             access to MSR_IA32_MCG_EXT_CTL]
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0a3ccb0..943609f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2984,6 +2984,13 @@
 			return 1;
 		msr_info->data = vmcs_read64(GUEST_BNDCFGS);
 		break;
+	case MSR_IA32_MCG_EXT_CTL:
+		if (!msr_info->host_initiated &&
+		    !(to_vmx(vcpu)->msr_ia32_feature_control &
+		      FEATURE_CONTROL_LMCE))
+			return 1;
+		msr_info->data = vcpu->arch.mcg_ext_ctl;
+		break;
 	case MSR_IA32_FEATURE_CONTROL:
 		msr_info->data = to_vmx(vcpu)->msr_ia32_feature_control;
 		break;
@@ -3075,6 +3082,14 @@
 	case MSR_IA32_TSC_ADJUST:
 		ret = kvm_set_msr_common(vcpu, msr_info);
 		break;
+	case MSR_IA32_MCG_EXT_CTL:
+		if ((!msr_info->host_initiated &&
+		     !(to_vmx(vcpu)->msr_ia32_feature_control &
+		       FEATURE_CONTROL_LMCE)) ||
+		    (data & ~MCG_EXT_CTL_LMCE_EN))
+			return 1;
+		vcpu->arch.mcg_ext_ctl = data;
+		break;
 	case MSR_IA32_FEATURE_CONTROL:
 		if (!vmx_feature_control_msr_valid(vcpu, data) ||
 		    (to_vmx(vcpu)->msr_ia32_feature_control &
@@ -6484,6 +6499,8 @@
 
 	kvm_set_posted_intr_wakeup_handler(wakeup_handler);
 
+	kvm_mce_cap_supported |= MCG_LMCE_P;
+
 	return alloc_kvm_area();
 
 out8:
@@ -11109,6 +11126,16 @@
 	return ret;
 }
 
+static void vmx_setup_mce(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.mcg_cap & MCG_LMCE_P)
+		to_vmx(vcpu)->msr_ia32_feature_control_valid_bits |=
+			FEATURE_CONTROL_LMCE;
+	else
+		to_vmx(vcpu)->msr_ia32_feature_control_valid_bits &=
+			~FEATURE_CONTROL_LMCE;
+}
+
 static struct kvm_x86_ops vmx_x86_ops = {
 	.cpu_has_kvm_support = cpu_has_kvm_support,
 	.disabled_by_bios = vmx_disabled_by_bios,
@@ -11238,6 +11265,8 @@
 	.set_hv_timer = vmx_set_hv_timer,
 	.cancel_hv_timer = vmx_cancel_hv_timer,
 #endif
+
+	.setup_mce = vmx_setup_mce,
 };
 
 static int __init vmx_init(void)